Method and apparatus for testing ceramic specimens by simultaneous application of mechanical and thermal stresses
AssigneesNGK Ceramics Europe S.A., NGK Insulators, Ltd.
InventorsKeiji Matsuhiro, Carine A. M. C. Dewitte, Jeffrey P. J. Pattimore
Life of this patent
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Abstract
A method and apparatus for testing a ceramic member applies mechanical stress to the member by application of mechanical force and simultaneously applies thermal stress by creating a temperature gradient in the member by localized heating of a portion thereof. The mechanical stress is impact stress or may be applied by application of a static load to the ceramic member. The method is especially applied to the proof-testing a plurality of ceramic members for quality assurance, particularly engine valve members.
Claims27
A method of proof-testing a plurality of ceramic engine valve members for quality assurance, wherein each valve member has a stem, a head at one end of the stem, an annular seating face on the side of the head towards the stem and a head face at the side of the head facing away from the stem, the method comprising subjecting each valve member (a) to mechanical stress applied by pressing the seating face against a tool and (b) simultaneously with said mechanical stress, to thermal stress applied by locally heating a central region of the head face.
Apparatus for testing a ceramic engine valve member comprising a tool adapted to contact a predetermined portion of the valve member, means for pressing said tool against the valve member to apply mechanical stress to the valve member, and heating means for local heating a predetermined portion of the valve member to apply thermal stress simultaneously with the application of said mechanical stress,
- wherein said tool is a striker member and said pressing means includes a holder for the valve member and means for relatively moving said striker member and said holder to cause said striker member to apply impact load to the valve member.
Apparatus for testing a ceramic engine valve member comprising a tool having a region shaped and adapted to contact an annular seating face of the valve member, means for pressing said tool against said seating face of the valve member to apply mechanical stress to the valve member, and heating means arranged for locally heating a predetermined portion of a head face of the valve member to apply thermal stress to the valve member simultaneously with the application of said mechanical stress.
A method of proof-testing a ceramic engine valve member for quality assurance, wherein the valve member has a stem, a head at one end of the stem, an annular seating face on the side of the head towards the stem and a head face at the side of the head facing away from the stem, the method comprising subjecting the valve member (a) to mechanical stress applied by pressing the seating face against a tool and (b) simultaneously with said mechanical stress, to thermal stress applied by locally heating a region of the head face.
Dependencies are inferred from the claim text.